President Barack Obama aims to announce tomorrow that Chrysler LLC will be placed into Chapter 11 bankruptcy, leading to an alliance with Italian automaker Fiat SpA, people involved in the matter said.

Administration officials are still resolving outstanding issues, and the plan isn’t finished, said one of the people, who declined to be named because discussions are private.

As part of negotiations, the U.S. Treasury raised its offer to Chrysler’s lenders to $2.25 billion in cash to forgive $6.9 billion in secured debt, two other people familiar with the matter said. The previous offer had been for $2 billion in cash.

Any bankruptcy filing may come as soon as tomorrow, people familiar with that matter said. Chrysler’s best assets would be sold to a new entity that would have an ownership structure similar to that envisioned in an out-of-court deal between the Auburn Hills, Michigan-based automaker and Fiat, based in Turin, Italy, the people said.

The Italian company would become a 20 percent owner of Chrysler, and a union retiree health-care trust fund would hold 55 percent, with the rest of the company staying in the government’s hands initially, the people said.

Fiat and the new board of directors of the company would pick a chief executive officer and chairman, said current CEO Robert Nardelli in a memo to workers on Feb. 17. Fiat’s chief, Sergio Marchionne, said in an April 15 interview that he would be willing to run Chrysler if asked.

Chrysler has made progress in its out-of-court restructuring, including reaching labor deals with the United Auto Workers union and Canadian Auto Workers on new contracts. Nardelli said today in a memo to employees that the company is waiting to hear whether its 46 lenders will agree to take cash to wipe out $6.9 billion in secured debt.

The possibility exists that a bankruptcy filing won’t be needed, one person said. Calls and e-mails to Chrysler spokeswomen, Lori McTavish and Shawn Morgan, seeking comments weren’t immediately returned. Jenni Engebretsen, a Treasury spokeswoman, didn’t immediately return an e-mail seeking comment.

One issue remaining is the U.S. government’s effort to combine Chrysler Financial and GMAC LLC, the lending units affiliated with Chrysler and General Motors Corp.

The government seeks to ensure that Chrysler has a well- capitalized credit arm, as required by Obama’s automotive task force, said people familiar with the situation.

Sheila Bair, chairman of the Federal Deposit Insurance Corp., has expressed concern that such a combination would involve her agency guaranteeing its debt, according to two people familiar with her views.

Bair is reluctant to be drawn into bailing out auto-finance companies to the potential detriment of the FDIC’s deposit insurance fund, according to the people, who asked not to be identified because the discussions are private.

Andrew Gray, an FDIC spokesman, Amber Gowen, a Chrysler Financial spokeswoman, and Gina Proia, a spokeswoman for GMAC, declined to comment.

Fiat will produce its first model with Chrysler in 2011 if the accord between the companies is approved, Marchionne said March 27.

Chrysler is considering producing models in the U.S. based on Fiat’s 500 small car, Punto and Panda, Steve Landry, executive vice president of sales, said Jan. 23. Fiat-based models will need engineering changes to comply with U.S. emissions rules, and Chrysler may use more powerful engines to match consumer preferences.

In its Feb. 17 viability plan, Chrysler forecast $6.9 billion of cost savings and additional revenue with Fiat through 2016, with a boost to earnings of at least $1 billion starting in 2012. Fiat and Chrysler will develop seven new small cars, according to the plan.

Fiat has been trying to bring back its main brands in the U.S. after 14 years and had held talks with the three automakers in the country last year on possible cooperation on production of Alfa Romeo cars. Marchionne also held talks with governments including Ontario for possible production in North America, before officially postponing the plan in October to 2011.

Marchionne restored profit at Fiat in 2005 after introducing new models and sharing more components among cars and through cooperation projects with competitors. Fiat has several partnerships including cooperation with PSA Peugeot SA on commercial vehicles, joint platforms with Ford Motor Co. and cooperation with Tata Motors Ltd.